Painting robot and associated operating method

ABSTRACT

An exemplary painting robot and corresponding operating methods for the same are disclosed. The robot may be configured to paint motor vehicle bodies on an outer surface and an inner surface with an atomizer that is guided by the painting robot. According to the exemplary illustrations, the painting robot is suitable for painting the outer surfaces and for painting the inner surfaces of the motor vehicle bodies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase application claiming the benefit ofInternational Application No. PCT/EP2009/001641, filed Mar. 6, 2009,which claims priority to German Patent Application Nos. DE 10 2008 015258.7, filed Mar. 20, 2008, DE 2008 015 494.6, filed Mar. 25, 2008, andDE 2008 037 035.5, filed Aug. 8, 2008. The complete disclosures of eachof the above-identified applications are hereby expressly incorporatedby reference herein in their entireties.

BACKGROUND

The present disclosure relates to a painting robot for painting motorvehicle bodies according to the preamble of claim 1. Here, “paintingrobots” are to be understood to mean any program-controlled multi-axiscoating machines or other movement machines. The present disclosure alsorelates to a corresponding operating method for such a painting robot.

In modern painting installations for painting motor vehicle bodies, useis made of multi-axis painting robots which guide as an applicationdevice for example a rotary atomizer and allow a highly efficientpainting operation.

Color changes are sometimes or often necessary if the motor vehiclebodies are to be painted with differently colored paints. The knownpainting robots therefore have a color changer described, for example inDE 103 35 358 A1. Known painting robots may have a color changer that isconnected on the inlet side to a plurality of color feed lines, viawhich differently colored paints are supplied. In the color changer, theindividual color feed lines may open via a respective color valve into acommon central color channel which, via a paint pressure regulator and ametering pump, supplies the rotary atomizer with the paint to beapplied.

In this design of the color changer, the central color channel betweenthe color changer and the main needle valve of the atomizer mustgenerally be flushed in the event of a color change before a differentpaint having a new color can be applied. The flushing of the centralcolor channel in the event of a color change is important since thepaint residues remaining in the central color channel in the event of acolor change would otherwise contaminate the new paint.

However, one problem here is the fact that, in the event of a colorchange, the volume of paint between the color changer and the mainneedle valve of the atomizer must be discarded so that, in the case of acolor changer having 24 possible colors for example, a paint loss ofbetween 45 and 55 ml occurs. In order to minimize the paint lossesoccurring during a color change, therefore, the color changer istypically mounted as close as possible to the atomizer, that is to sayin the distal robot arm, which is also known as “arm 2”, and to which awrist (hand axis) for the atomizer is attached.

However, the mounting of the color changer in the distal robot arm hasuntil now required such a large amount of space in the distal robot armthat the known painting robots having a color changer mounted in thedistal robot arm are suitable only for exterior painting, that is to sayfor the painting of outer faces of the motor vehicle bodies, since inexterior painting the size of the distal robot arm plays only asubordinate role.

By contrast, for painting the interior of motor vehicle bodies, it hasto date not been possible to use any painting robots in which the colorchanger is mounted on the distal robot arm, since painting of theinterior requires narrow, slim robot arms which can be introduced andarticulated through body openings (e.g. door openings) into the interiorof the motor vehicle bodies in order to be able to paint the inner facesin the interior. In the case of the known painting installations forpainting motor vehicle bodies, therefore, in order to paint theinterior, use is made of painting robots having a different design, inwhich the color changer is not mounted on the distal robot arm, thehigher paint losses being accepted in order to allow a slimmer design ofthe distal robot arm to permit the robot to extend through a vehicleopening, or instead complex technologies such as, for example, paintcontainers within in the atomizer or pigging systems with pistonmetering means.

One disadvantage with the known painting installations, therefore, isthe fact that different types of robots have to be used for interiorpainting on the one hand and for exterior painting on the other hand,which generally, and in any event in the case of a non-optimal design,also requires different application technology. However, the differentdesigns of the painting robots and of the associated applicationtechnology lead to increased effort and cost in terms of constructionand logistics of coating installations.

Accordingly, there is a need for a correspondingly improved paintingrobot.

BRIEF DESCRIPTION OF THE FIGURES

While the claims are not limited to the specific illustrations describedherein, an appreciation of various aspects is best gained through adiscussion of various examples thereof. Referring now to the drawings,illustrative examples are shown in detail. Although the drawingsrepresent the exemplary illustrations, the drawings are not necessarilyto scale and certain features may be exaggerated to better illustrateand explain an innovative aspect of an illustration. Further, theexemplary illustrations described herein are not intended to beexhaustive or otherwise limiting or restricting to the precise form andconfiguration shown in the drawings and disclosed in the followingdetailed description. Exemplary illustrations are described in detail byreferring to the drawings as follows:

FIG. 1 shows a perspective view of a painting robot according to anexemplary illustration;

FIG. 2 shows a perspective view of the distal robot arm (“arm 2”) of thepainting robot according to an exemplary illustration;

FIG. 3 shows another perspective view of an exemplary distal robot arm;

FIG. 4 shows a perspective view of a color bar which is part of a colorchanger, according to one exemplary illustration;

FIG. 5 shows a schematic view of the docking system in the paintingrobot according to an exemplary illustration;

FIGS. 6A, 6B show schematic cross-sectional views of different designsof the color bar, according to an exemplary illustration;

FIGS. 7 and 8 show connection of the individual color lines to the colorchanger, according to an exemplary illustration;

FIGS. 9A-9D show different operating states of the exemplary paintingrobot in the context of the so-called “push-out mode”;

FIG. 10 shows the “push-out mode” in the form of a flowchart;

FIGS. 11A-11E show different operating states of the painting robot inthe context of the so-called “reflow mode,” according to an exemplaryillustration;

FIG. 12 shows the “reflow mode” in the form of a flowchart;

FIGS. 13A-13H show different operating states of an A/B system for thepush-out mode and a corresponding temporal sequence diagram, accordingto an exemplary illustration;

FIGS. 14A-14H show different operating states of an A/B system for thereflow mode and a corresponding temporal sequence diagram, according toan exemplary illustration;

FIG. 15 shows a valve arrangement which is suitable in particular forthe A/B systems according to an exemplary illustration;

FIG. 16 shows a modular color bar of a color changer which is suitablefor the painting robot, according to an exemplary illustration;

FIG. 17 shows a schematic view of one module of the color bar from FIG.16, according to an exemplary illustration;

FIG. 18 shows the rear side of the color bar of FIG. 16, according to anexemplary illustration;

FIG. 19 shows a view of one module of the color bar of FIG. 16 whichoperates with color circulation, according to an exemplary illustration;

FIG. 20 shows the rear side of the exemplary module of FIG. 19;

FIG. 21 shows a view of the valve arrangement of the exemplary module ofFIG. 19 with the pipes in the interior of the module body which areconnected to the valves, according to an exemplary illustration;

FIG. 22 shows a module for a special color supply which is suitable foradding to a color bar as shown in FIGS. 16-18, according to an exemplaryillustration;

FIG. 23A shows a schematic view of the valve arrangement of theexemplary module of FIG. 22 and the connection thereof to the atomizerof the painting robot, according to an exemplary illustration; and

FIG. 23B shows a detail view of the valve arrangement of the exemplarymodule for the special color supply in the color bar of FIG. 23A,according to an exemplary illustration.

DETAILED DESCRIPTION

The exemplary illustrations encompass the general technical teaching ofproviding a painting robot which is suitable in design terms, e.g., dueto an advantageous arrangement of components with a small spacerequirement, both for painting the outer faces of motor vehicle bodiesand for painting the inner faces of the motor vehicle bodies.

For example, an exemplary robot is able to introduce the atomizerthrough door openings (and in special cases through window openings)into the interior of the body in the assembled state, that is to saywith doors and hoods as obstacles, in the engine and trunk compartmentsof the body, and to an extent sufficient for painting the interior. Intypical cases, the vertical height of the “arm 2” (or of the distalmachine arm in other painting machines) with the arm in the horizontalposition may be no greater than 350 millimeters (mm), and in at leastone exemplary illustration no greater than 300 mm, in the region of itsatomizer-side end. Additionally, a maximum width measured transverselythereto in this region may be no greater than 300 mm, and in at leastone exemplary illustration no greater than 250 mm, wherein the verticalheight of the arm is usually more important than its width. These limitsfor sufficiently flat (height) and/or narrow (width) dimensioninggenerally may advantageously be observed along a sufficient length inthe direction of the pivot axis of this arm, for example up to at least300 mm proceeding from the attachment face of the hand axis, in othercases up to 500 mm. In its rear region the arm may then be wider, e.g.for lateral tube exit, and also higher for design reasons.

Such slim robot arms may be employed for the interior painting ofbodies, but for space reasons they have to date not been able to containthe components necessary for exterior applications, such as colorchangers, metering pumps, paint pressure regulators, etc., and thereforethey had the aforementioned disadvantages such as paint losses, flushinglosses and time losses, etc.

An exemplary painting robot generally comprises one or more robot armsfor spatially positioning an application device (e.g. a rotary atomizer,air atomizer, airless atomizer or ultrasonic atomizer). Any applicationdevice may be employed that is convenient. The robot arms may bearranged kinetically in series or also in parallel, or in combinedseries and parallel. For example, the parallel kinematics as generallydescribed in EP 1 614 480 B1 Justin regard to a single (the distal) armmay also be considered. In the exemplary painting robot, the distalrobot arm (i.e. the so-called “arm 2”) is by contrast so narrow and slimthat the distal robot arm with the application device mounted thereoncan advantageously be introduced through body openings (e.g. windowopenings) into the interior of the motor vehicle bodies in order topaint the inner faces therein.

Furthermore, the exemplary painting robot may advantageously include acolor changer which, in order to minimize the paint losses occurring inthe event of a color change, may be mounted on the distal robot arm(“arm 2”) of the painting robot, which is achieved by a special designof the color changer without impairing the suitability for interiorpainting.

In one exemplary illustration, the color changer comprises a pluralityof docking points (e.g. on a color bar) which are supplied with thedifferently colored paints by the individual color feed lines. Inaddition, the color changer in this example comprises a movable colorextractor (e.g. a docking carriage) which can selectively dock onto oneof the docking points and, in the docked state, extracts the paint fromthe associated color feed line and supplies the extracted paint to thecommon color line. In order to select the paint having the desiredcolor, the color extractor is therefore positioned in such a way thatthe color extractor docks onto the associated docking point, whereuponthe paint can be extracted from the associated color feed line via thedocking point. In contrast to known color changers, e.g., as describedabove, therefore, in this example the color changer does not have acentral color channel, so that the color changer, due to its design andeven in the event of a malfunction of the color valves or an incorrectactuation of the color valves, prevents any paint contamination frombeing able to occur since in each case only one single color feed lineis connected to the color extractor.

Also in the above-described exemplary color changer, there may bearranged in the individual color feed lines a respective color valvewhich selectively blocks or enables the paint flow through therespective color feed line. In this case, the individual color valvesare in each case controlled by one and the same control signal, whereinthis may be for example a pneumatic, electrical or mechanical controlsignal. The control signal for actuating the individual color valves mayadvantageously be passed from the color extractor via the respectivelydocked docking point to the respective color valve, so that the controlsignal can reach one of the color valves only when the color extractoris docked onto the associated docking point. This type of actuation ofthe color valves inherently ensures that the individual color valves canbe opened only when the color extractor is docked onto the associateddocking point. The individual color valves may thus be designed in sucha way that the color valves block the associated color feed line whenthere is no control signal. As the color valves or instead ofconventional color valves, use may also be made of elements known as“quick-locking” or “quick-connect” couplings, externally actuatednon-return valves or valves which open as a result of actuation by aplunger.

The movable color extractor may be, for example, a docking carriagewhich is linearly displaceable relative to the docking points of theindividual color feed lines. However, it is also possible as analternative that the color extractor is rotatable in order to dock ontothe desired docking point.

In one exemplary illustration, a color changer generally as described inthe patent application EP 1 245 295 A2 may be incorporated, so that thecontent of said patent application is hereby fully incorporated byreference herein in its entirety.

Furthermore, the exemplary painting robot may comprises two separateflushing circuits, e.g., a first flushing circuit for flushing thedocking points of the color changer, and a second flushing circuit forflushing the common color line for the differently colored paintsbetween the color changer and the atomizer. The two flushing circuitsmay be separate or at least can be separated, so that the docking pointscan be flushed independently of and separately from the common colorline. With this design, therefore, it is possible that the common colorline for the differently colored paints is flushed as far as theatomizer, while the docking points of the color changer are beingflushed simultaneously or at least in a temporally overlapping manner.This simultaneous or temporally overlapping flushing reduces the colorchange time in the event of a color change. In addition, during a colorchange, the color extractor can already approach and dock onto a newdocking point while the common color line for the differently coloredpaints is being flushed as far as the atomizer, which likewise helps toachieve a reduction in the necessary color change time.

With this design, the separation of the two flushing circuits may takeplace by means of at least one separating valve which is arranged in thecolor extractor.

In this case, the first flushing circuit may lead from a flushing agentfeed line via a flushing agent valve through the common color linedownstream of the separating valve to the atomizer and finallyoptionally via a return valve into a return line or via the main needlevalve of the atomizer. In the context of the exemplary illustrations,therefore, there are various possibilities for the flushing of thecommon color line.

On the one hand, it is possible that, after the flushing of the commoncolor line, the thinning fluid which may serve as the flushing agent issprayed out by the atomizer in the same way as the paint to be applied.In this case, the flushing agent introduced into the common color lineacts as a displacement medium and pushes out via the atomizer the paintstill located in the color line. Also possible is the mode of operationreferred to as the “push-out mode”, in which the residual paint stilllocated in the line and sprayed out by the atomizer continues to be usedpractically in its entirety for painting until finally the flushingagent which serves as the displacement medium is dispensed by theatomizer. In this “push-out mode”, therefore, precise knowledge of theswitchover time at which the color valve is closed and the flushingagent valve is opened is generally necessary. The painting operationmust then be terminated with a sufficient safety time interval beforethe flushing agent which serves as the displacement medium is dispensedby the atomizer. A “push-out” can be carried out in any manner that isconvenient, e.g., by using a pig which pushes the paint, wherein the pigcan be pushed by the flushing agent. However, if the residual paint ispushed directly by a flushing agent (the same applies to the reflowmode), lines which have a sufficiently small tube diameter are necessaryin order to avoid the known “lance effect”. The internal diameter of alllines and channels in components through which paint is pushed directlyby the flushing agent or other pushing medium may be smaller than 6 mm.For example, in one illustration the internal diameters are betweenapproximately 2 and approximately 4 mm. Furthermore, these lines andchannels may also avoid corners and sharp bends with regard to the lanceeffect and in order to avoid swirling, etc.

On the other hand, for the flushing of the common color line, it ispossible that there is arranged in the atomizer a first return valve,via which the flushing agent can be drained off into a return line.

The two types of flushing mentioned above can also be combined with oneanother by first using the paint pushed out of the common color line bythe flushing agent for painting purposes. Shortly before the flushingagent reaches the main needle valve of the atomizer, the main needlevalve is then closed and the return valve in the atomizer is opened sothat the flushing agent is not sprayed out.

Furthermore, the color change system according to the exemplaryillustrations allows reuse of the paint located in the common color linebetween the color changer and the atomizer by pushing the paint locatedin the common color line between the color changer and the atomizer inthe event of a color change back via the docking point into theassociated color feed line, for which reason this operating mode is alsoknown as the “reflow mode”. The pushing of the paint back out of theline section of the common color line between the color changer and theatomizer into the color feed line may take place by virtue of the factthat a pushing agent which serves as a displacement medium, such as e.g.flushing fluid, is introduced into the common color line in the regionof the atomizer upstream of the main needle valve of the atomizer. Theflushing agent introduced into the common color line then pushes thepaint located in the common color line back into the associated colorfeed line. In this example, therefore, a flushing agent feed line mayopen into the common color line upstream of the main needle valve of theatomizer via a flushing agent valve arranged in the atomizer, in orderto push the paint remaining in the common color line back through thecolor changer into the associated color feed line for later reuse, theintroduced flushing agent serving as a displacement medium.

The reflow mode can also be carried out in any manner that isconvenient, e.g., by using a pig.

The introduction of the displacement medium or pushing medium, forexample of a solvent or flushing agent, into the atomizer mayadvantageously not take place directly via the flushing agent feed lineand the flushing agent valve but rather may take place via a flushingagent metering means which is arranged in the flushing agent feed lineupstream of the flushing agent valve and which can push the flushingagent located in the flushing agent metering means into the common colorline when the flushing agent valve is opened.

“Metering means” in this case means a device which is intended to conveya predefined volume of liquid (dose) but, in contrast to the meteringpumps used for coating material, does not have to produce a definedvolume flow per unit of time.

Such a metering means, e.g. a piston metering means, which mayadvantageously be acted upon only by pressure and operates withoutdefined time or speed control, has significant advantages e.g. over atoothed wheel metering pump operating volumetrically. Besides the lowcontrol complexity, the advantage of much lower losses is obtained inparticular, said losses in the case of metering pumps being caused byslip and becoming greater constantly and moreover in an undefined mannerdue to wear during operation.

A further flushing agent valve for controllably filling the flushingagent metering means via the flushing agent feed line may be locatedupstream of the flushing agent metering means. On the inlet side,therefore, the flushing agent metering means may be filled with theflushing agent from the flushing agent feed line via the flushing agentvalve. By contrast, on the outlet side, the flushing agent meteringmeans may be connected via the flushing agent valve to the common colorline in order to be able to meter into the common color line theflushing agent which serves as a displacement medium.

In one exemplary illustration, the flushing agent metering means has ametering volume which is substantially identical to the filling volumeof the color line between the respectively docked color valve and themain needle valve of the atomizer. The metering volume of the flushingagent metering means is thus sufficient to fill the entire line sectionof the common color line between the color changer and the atomizer withthe flushing agent which serves as the displacement medium, and thus topush back into the associated color line the paint located in this linesection.

By way of example, the flushing agent metering means for the “reflowmode” may be designed as a metering cylinder or may be formed by apigging tube.

There are various possibilities for the drive of the flushing agentmetering means, wherein the flushing agent metering means may beelectrically or pneumatically driven.

It has already been explained above that the exemplary color changer mayinclude a movable color extractor which can dock onto one of a pluralityof docking points in order to extract the paint of the desired colorfrom the associated color feed line via the docking point. In this case,there may advantageously be provided a clamping device whichmechanically clamps together the color extractor (e.g. the dockingcarriage) and the respective docking point (e.g. in the color bar) inthe docked state. This advantageously makes it possible for the colorextractor to dock onto the respective docking point without any externalforce, so that no holders or supports of large size are necessary.

In one exemplary illustration, the clamping device comprises a groovewith an undercut, onto which a movable clamping element latches. By wayof example, the individual color feed lines and the associated colorvalves and docking points may be arranged in a row in a color bar,wherein the color bar has the groove for clamping to the colorextractor. In this case, the color extractor may consist of a dockingcarriage which is displaceable relative to the color bar in thelongitudinal direction of the groove, wherein the docking carriage canpull toward itself by means of a docking cylinder a gripping disc guidedin the groove in order to clamp the docking carriage to the color bar.

Despite the clamping between the docking carriage on the one hand andthe color bar on the other hand, a leakage may occur in the region ofthe docking points in the event of a fault, e.g. in the event of failureof one of the seals provided therein, whereby paint escapes into thegroove in the color bar. It is therefore advantageous if the groove hasno undercut on its underside so that paint which has escaped as a resultof a leakage can flow downward out of the groove. In one example,therefore, the groove has an undercut only on its upper groove flank,whereas the groove has no undercut on its lower groove flank.

It has already been mentioned in the introduction that the color changermay advantageously be mounted on the distal robot arm (“arm 2”) so thatthe common color line between the color changer and the atomizer is asshort as possible, which leads to correspondingly low losses during acolor change. In addition, a paint pressure regulator and/or a meteringpump for the coating material may also advantageously be mounted on thedistal robot arm, so that generally essential parts of the applicationtechnology are located on the distal robot arm. Furthermore, it isadvantageous if there is also arranged in the distal robot arm aservo-pneumatic actuator for moving the color extractor (e.g. thedocking carriage) relative to the docking points (e.g. on the color bar)in order to select the paint having the desired color.

Here, a “metering pump” for metering the coating material means aconveying device by means of which the volume flow, that is to say thevolume of material conveyed per unit of time, can be changedautomatically during the application, e.g. depending on the sub-areaspresently being coated on the object to be coated. Typical examples ofmetering pumps include piston metering means driven by an electric motoror in particular toothed wheel pumps or other rotary displacement pumps.The change in the metering rate according to requirements can beachieved in any manner that is convenient, e.g., by controlling therotary speed of the drive motor of the metering pump.

Furthermore, it is advantageous if the paint pressure regulator, theactuator for the color extractor and/or the metering pump are arrangedin a common connection block, thereby omitting connecting tubes betweenthe paint pressure regulator and the metering pump and thus disruptionscaused by the tubes. In addition, the integration of the paint pressureregulator and of the metering pump in a single connection block allowsshort connection lengths and also a simple and compact design. The paintpressure regulator may be installed directly on the metering pump.

In another exemplary illustration, a particular connection of theindividual color feed lines to the color changer may be provided. Morespecifically, receiving bores for each of the individual color lines maybe arranged in the color changer, into which bores the color feed linesare inserted for connection to the color changer. At their free end, thecolor feed lines in this case have an angled clamping surface, which mayconsist for example of a conical outer surface running coaxially to thereceiving bore. Also located in the color changer is a clamping borewhich runs substantially at a right angle to the receiving bore andopens into the receiving bore, wherein the clamping bore has an innerthread. A clamping screw (e.g. an Allen screw, Torx screw, slotted screwor cross-head screw or the like) can then be screwed into the clampingbore, which screw presses with its free end against the angled clampingsurface at the free end of the color feed line and thus axially securesthe color feed line and clamps it in the receiving bore.

The above-described exemplary connection design is also suitable forconnecting other lines.

Furthermore, the exemplary illustrations also include a correspondingoperating method for a painting robot, wherein the painting robot isused both for painting the outer faces and for painting the inner facesof the motor vehicle bodies.

In the event of a color change, an exemplary operating method mayprovide that the movable color extractor (e.g. a docking carriage) ofthe color changer is docked onto one of a plurality of docking points(e.g. on a color bar) which are supplied with differently colored paintsfrom a plurality of color feed lines.

After docking, the paint to be applied may then be extracted from theassociated color feed line via the docked docking point, and theatomizer may be supplied with the paint selected by the color changervia a common color line for the differently colored paints.

Furthermore, an exemplary operating method may provide that the dockingpoints in the color changer are flushed with a flushing agent via afirst flushing circuit, whereas the common color line between the colorchanger and the atomizer is flushed with a flushing agent via a secondflushing circuit, wherein the first flushing circuit is separate or isseparated from the second flushing circuit.

Advantageously, the docking points and the common color feed linebetween the color changer and the atomizer may in this case be flushedsimultaneously or at least in a temporally overlapping manner in orderto shorten the necessary flushing time and thus also the color changetime.

The two flushing circuits may be separated from one another by at leastone separating valve in order to allow the simultaneous or temporallyoverlapping flushing.

In the context of the “push-out mode” already mentioned above, theexemplary operating methods may provide in the event of a color changethat the paint remaining in the common color line is pushed out of thecommon color line via the second flushing circuit optionally through areturn valve located in the atomizer into a return line or via the mainneedle valve of the atomizer.

By contrast, in the “reflow mode” already mentioned above, the exemplaryoperating methods may provide that the paint remaining in the commoncolor line is pushed back into the associated color feed line via thedocking point of the color changer and is later reused.

The exemplary illustrations described herein may be suitable also forthe application of two-component paints, wherein the additionalcomponents required, such as e.g. two metering pumps, can likewise beaccommodated in the slim arm of the painting machine.

The exemplary illustrations are just as suitable as conventionalpainting robots, with color changers arranged in the vicinity of theatomizer, for electrostatic coating both with conductive paint such ase.g. water-based paint and also for other coating material with directcharging or external charging. In the case of non-conductive paints andthe direct charging thereof in the atomizer, the exemplary docking colorchanger can be at the high-voltage potential of the atomizer, since thepaint column between the color changer and the low-electrical potentialor grounded color supply part of the robot is sufficient for insulationpurposes. By contrast, in the case of conductive paint, the colorchanger may be grounded if, for example, a rotary atomizer with externalelectrodes is used.

FIGS. 1 to 8 show different views and parts of an exemplary paintingrobot 1 which is used in a painting installation for painting motorvehicle bodies, wherein the painting robot 1 is suitable both forpainting the outer faces of the motor vehicle bodies and also forpainting the inner faces of the motor vehicle bodies, as will bedescribed in more detail below.

The painting robot 1 may be of any known design that is convenient. Therobot 1 may include a robot base 2, which in this example can be fixedlymounted on a machine plinth. As an alternative, however, it is alsopossible to mount the robot base 2 with appropriate modification in amanner such that it can be displaced linearly on a rail, so that thepainting robot 1 can move in the painting booth, e.g., parallel to theconveying direction of the motor vehicle bodies to be painted. For thepurpose described here, it may also be advantageous to mount the rail ina raised manner, e.g., as generally described in (EP 1 609 532 A1).Accordingly, the robot 1 may be disposed at the height of the upper partof the body or above the roof thereof.

A robot arm 3 may be rotatably mounted on the robot base 2, wherein therobot arm is rotatable about a perpendicular axis of rotation relativeto the robot base 2. A further robot arm 4 may be pivotably mounted onthe robot arm 3.

Finally, a distal robot arm 5 may be pivotably mounted at the distal endof the robot arm 4, wherein the robot arm 5 guides an applicationelement such as a rotary atomizer 7 via a conventional, e.g. three-axisor four-axis, robot hand axle 6.

The distal robot arm 5 is shown here without any housing cover, so thatit can be seen that essential parts of the application technology aremounted on the distal robot arm 5. For example, as shown in FIG. 2 acolor changer 8, a paint pressure regulator 9, a metering pump 10 formetering a stock paint and, in the example considered here concerningthe application of two-component paints, a metering pump 11 for meteringa hardener. The paint pressure regulator 9 may be any type that isconvenient.

The color changer 8 comprises a so-called color bar 12 which is suppliedwith differently colored paints via numerous color feed lines 13,wherein the individual color feed lines 13 in the color bar 12 open viaa respective color valve 14 (FIG. 5) into a respective docking point 15,from which the desired paint can be extracted. As color valves 15 with asmall space requirement, needle valves which are advantageouslycontrolled electrically or by a pneumatic piston drive and which haveconical valve needles at their end may be provided. For example, colorchangers as described in DE 198 46 073A1, EP 1 250 964 B1, DE 10 2007037 663.6 may be employed.

As will be explained in more detail below (FIGS. 16-18), the colorvalves 14 (FIG. 5) may be arranged, e.g., in a side face of the colorbar 12 in one or more rows parallel to the longitudinal directionthereof (direction of the arrow in FIG. 3), with needle axes arrangedtransversely or perpendicular to this side face and thus parallel to thedocking direction (of the linear drive 17 in FIG. 5). As is shown, theassociated docking points 15 (FIG. 4) may likewise be located at equaldistances from one another in one or more rows parallel to thelongitudinal direction, e.g. in the side face of the color bar 12,advantageously on the side of the color bar 12 opposite the colorvalves. In the case of the illustrated arrangement with two rows, thedocking points of one row may in each case be offset in the longitudinaldirection of the color bar by half the distance between adjacent dockingpoints relative to the docking points of the other row.

Furthermore, the color changer 8 may include a docking carriage 16 whichis displaceable in the direction of the arrow (cf. FIGS. 2 and 3)relative to the color bar 12 in the longitudinal direction of thelatter, wherein the docking carriage 16 is positioned in the directionof the arrow by, e.g., a servo-pneumatic linear drive 17 operating inany manner that is convenient with a pneumatic cylinder, in order todock onto the desired docking point 15 of the color bar 12. As analternative, a drive with an electric motor or some other linear drivewhich is controllable by stored control data may be used.

For precise positioning at the docking points, the linear drive may beprovided with a measuring device 32 (FIG. 2) in any manner that isconvenient. Since the atomizer 7 and in some cases also parts of therobot arm 5 may be under high voltage during operation, the measuringdevice 32 may in these cases be insulated against the high voltage. Inthe case of an electric measuring device, it may furthermore beencapsulated in order to meet the requirements for protection againstexplosion. The same applies to any other electrical elements present inthe robot arm.

The atomizer-side connection line arrangement of the docking carriage 16may be located in a U-shaped cable carrier chain or guide chain which ismovable parallel to the direction of displacement in the manner of aso-called energy chain as used on painting machines, said chain beingattached to the docking carriage at one end and fixed in a stationarymanner at the other end. The atomizer-side line arrangement is connectedto openings of the docking carriage 16 which are in each case alignedwith one of the rows of docking points 15 of the color bar 12. Furtherdocking openings may be provided in the docking carriage 16 for flushingpurposes and for pneumatic control signals for switching the colorvalves 14.

In the case of the color bar 12 for e.g. 24 colors which is shown inFIGS. 2 to 4, it is assumed that the color tubes are connected as stublines. If there is space for, e.g., twice the number of colorconnections, the color bar may also be designed for color circulation,as will be described in more detail below.

It can be seen from FIGS. 4 and 5 that the color bar 12 has a groove 18running in the direction of the arrow (FIGS. 2 and 3) between the tworows of docking points 15 provided in the example under consideration,an undercut being arranged on the upper side of said groove. A grippingdisc 19, which is guided by the docking carriage 16 via a pneumaticcylinder 20, slides in the groove 18 in the mounted state. With thepneumatic cylinder 20 serving as the docking and clamping cylinder, thedocking carriage and the color bar are displaceable transverselyrelative to one another. An electric motor drive or other drive couldalso be provided instead of the pneumatic cylinder 20.

In the docked state, the pneumatic cylinder 20 pulls the gripping disc19 toward itself, so that the gripping disc 19 pulls the undercut of thegroove 18 in the direction of the docking carriage 16, which leads to amechanical clamping between the docking carriage 16 on the one hand andthe color bar 12 on the other hand.

On the one hand, this mechanical clamping between the docking carriage16 and the color bar 12 allows a largely leakage-free docking onto thedocking points 15 of the color bar 12.

On the other hand, this type of mechanical clamping between the dockingcarriage 16 and the color bar 12 allows a docking without any externalforce, so that no complicated holders or supports are necessary in orderto press the docking carriage 16 against the color bar 12.

By contrast, the pressure of the pneumatic cylinder 20 is released inthe non-docked state in such a way that the gripping disc 19 can slidegenerally freely with play in the groove 18 so that the servo-pneumaticlinear drive 17 can freely position the docking carriage 16 in thedirection of the arrow in order to dock onto the desired docking point15.

It can also be seen from FIGS. 4 and 6A that the groove 18 has anundercut only on its upper side, while the groove 18 has no undercut onits underside and even has a groove flank inclined downward at an angle.This configuration of the groove 18 is advantageous because paint thathas escaped into the groove 18 due to a leakage can in this way simplyflow off and can easily be removed.

FIG. 6B shows an alternative configuration of the groove 18, wherein thegroove 18 is arranged outside the color bar 12.

In the illustrated example, the docking carriage 16 may be displaceablerelative to the color bar 12 which is mounted in a stationary manner inthe arm 5, but an inverse arrangement with a displaceable color bar isalso conceivable.

One advantage of the structure of the color changer 8 is the extremelyslim design, so that the distal robot arm 5 is likewise very slimdespite the application technology arranged thereon. This is importantbecause the distal robot arm 5 can in this way be easily insertedthrough body openings (e.g. window openings) into the motor vehicle bodyto be painted, in order to paint inner faces therein. Due to its slimdesign, the exemplary painting robot 1 is therefore suitable both forpainting inner faces and for painting outer faces. This offers thepossibility of using in a painting line just one single type of robotfor painting the motor vehicle bodies, which means a considerablesimplification.

FIGS. 2 and 3 show a connection block 21 in which the metering pump 10for the stock paint and the paint pressure regulator 9 and alsoassociated pressure sensors 33 may be integrated. The paint pressureregulator 9 may be installed directly and without any connecting tube onthe metering pump 10. This integration of the metering pump 10 and ofthe paint pressure regulator 9 in the connection block 21 offers theadvantage that disruptions between the paint pressure regulator 9 andthe metering pump 10 which are caused by the tubes are omitted alongwith the tubes. In addition, the integration of the paint pressureregulator 9 and of the metering pump 10 in the connection block 21brings the advantage of shorter connection lengths and also of a simpleand compact structure. In FIG. 2, 21′ denotes the second connectionblock for the two-component system mentioned above.

FIGS. 7 and 8 show an exemplary connection structure for connecting thecolor feed line 13 to the color bar 12. For instance, the individualcolor feed lines in each case have at their free end a plug-in nipple 22with a union nut 23, wherein the plug-in nipple 22 for connection to thecolor bar 12 is inserted into a corresponding receiving bore in thecolor bar 12. In order to fix the plug-in nipple 22 and thus also theassociated color feed line in the receiving bore of the color bar 12,the color bar 12 furthermore has a clamping bore which runstransversely, i.e. at a right angle or obliquely, to the receiving boreand opens into the receiving bore. In order to fix the plug-in nipple22, a clamping screw 24 is screwed into this clamping bore until theclamping screw 24 butts with its conical tip against a correspondinglyconically shaped clamping surface of the plug-in nipple 22. As theclamping screw 24 is screwed in further, the clamping screw 24 thenclamps the plug-in nipple 22 in the receiving bore, as a result of whichthe plug-in nipple 22 and the associated color feed line is also fixedin the receiving bore.

The clamping screw 24 may in this case be designed e.g. as an Allenscrew or the like so that, in order to connect the individual color feedlines 13, all that is required is an Allen key or the like which can bemanipulated between the individual color feed lines 13 more easily thanan open-ended wrench or a ring spanner. The individual connections ofthe color feed lines 13 to the color bar 12 can therefore be arranged atsmaller distances from one another, as a result of which the necessaryinstallation space is further reduced.

During the docking movement of the docking carriage 16 transversely tothe color bar 12, which may be carried out by the pneumatic cylinder 20(FIG. 5), it may be desirable to ensure that the docking inlet of thedocking carriage 16 is precisely centered in relation to the dockingopening 15 of the respectively approached color valve 14. To this end,there may be arranged on at least one of the two components 12, 16 oneor more centering pins (not shown) which can engage in a bore on therespective other components. This positioning is designed for a certaindegree of precision (e.g., 0.5 mm) which may be desirable, e.g., wherethe centering pins are not able to compensate any larger deviations(e.g. more than 0.5 mm) of the linear positioning by the e.g.servo-pneumatic linear drive 17 (FIG. 3) from the correct position.Deviations are possible since no sensor of the desired accuracy can orshould be used in the measuring device provided for the positioning. Forprecise positioning, the linear drive 17 may be operated in a controlloop, wherein nominal position values respectively stored for theindividual colors are compared with the actual positions determined forexample by the measuring device 32 (FIG. 2) and can be corrected in theevent of deviations.

With this positioning, however, the problem may exist that the storednominal position values do not always precisely coincide with the actualpositions of the docking openings 15. The reason for these errors lies,for example, in tolerances during manufacture of the color change systemor in tolerances of the measuring system. Tolerances which add to oneanother may arise for example during assembly of the color changer,e.g., in particular of the color bar 12 from individual modular segments(FIGS. 16-18). In addition to errors in the planar linear positioning,the actual docking position may also change due to static forces (e.g.depending on the angle of the robot arm) and acceleration forces of therobot movements. In the event of a nominal position value which does notprecisely coincide with the actual position of the docking opening andcorrection of this error by the centering pins, the control system willstill attempt after docking to approach the supposedly correct positioncorresponding to the nominal value. This may lead to a pressure build-upthrough the control loop up to the maximum pressure in the pneumaticcylinder of the linear drive so that, in the event of the subsequentundocking, the pneumatically pretensioned docking carriage suddenlyjumps to the incorrect nominal position or overshoots the latter. Theresult would be an undesired mechanical stress on the centering pins andthe associated bores.

In order to solve this problem, there are various possibilitiesaccording to the exemplary illustrations which can be implemented, forexample, by software functions of the docking control system.

According to a first possibility, the undesired mechanical stresses canbe avoided by the fact that, after docking, the control system reducesthe pressure in the pneumatic cylinder to zero or to a sufficiently lowvalue.

A second possibility lies in the fact that the control system carriesover as the new nominal position the actual docking position measuredafter docking (at least within a predefined permissible tolerance) andthus the undesirable counter-control is avoided. This new nominalposition may apply only until the subsequent undocking or else may alsobe stored as a future nominal position.

Another possibility is the statistical evaluation of the actual dockingpositions measured for the same color during an advantageous number(e.g. between three and fifty or even one hundred) respectivelypreceding docking processes, and the carrying-over of the average valuecalculated therefrom as the new nominal position. At least largerfluctuations and errors can be avoided as a result.

Furthermore, a mean position to be carried out as the nominal positionmay be calculated from determined upper and lower position limit valuesobtained as a result of the docked docking carriage being moved by theservo drive in both directions as far as the respective limit of theavailable movement play.

Further problems may occur in the position measuring system (measuringdevice 32). For instance, it may be the case that a position sensor usedin the measuring system for the actual position of the docking carriagesupplies different measured position values depending on its movementdirection. This hysteresis problem of the sensor can be solved by theindividual color valves 14 or the docking openings 15 thereof alwaysbeing approached in the same direction. The direction of approach wouldotherwise be random and would depend on the direction in which the colorvalve to be approached next is located, which may be advantageous inother situations. Instead of this, in order to avoid the aforementionedhysteresis problem, the respective next color valve is approacheddirectly in the same direction as the current color valve only when itlies in the same direction proceeding from a reference point (forexample the first color valve). If, on the other hand, the next colorvalve lies between the current color valve and the reference point, thedocking carriage with its docking inlet first moves back beyond the nextcolor valve to a point (e.g. to the first color valve) from where itreaches this next color valve after a change in direction.

One alternative possibility lies in storing for each docking positionnot just one nominal value as in the normal case but rather a respectivenominal value for each of the two possible directions of approach, saidvalue then being used in a manner depending on the direction of travelof the docking carriage.

Another potential problem of the position measuring system may be alinearity of the sensor behavior, i.e. of the measured value as afunction of the docking carriage travel, which is not sufficient for thenecessary position accuracy. Similar problems may be based on aging ofthe sensor or on wear or temperature faults of the measuring device.These and other problems can be solved by individual referencing,wherein, in order to create the control program, each color position isapproached individually by hand and then the relevant actual position isstored, so that the accuracy depends only on the reproducibility (whichis extremely precise per se). As an alternative possibility, it would besomewhat less complicated to approach manually or automatically only afirst docking point, to record the actual position and then to move thedocking carriage from there automatically over the distance known to thesystem to the next docking point, then to the next docking point, etc.For each docking point, with the pneumatic cylinder in the pressurelessstate, the measured position thereof is stored as the nominal valueuntil the complete table of all positions is available. Since thedistances between the docking points are small, correspondingly smalllinearity errors are obtained.

When creating the table of the nominal position values, it may beconvenient to carry out various checks with regard to correctness andcompleteness. On the one hand it is checked that the positions for twodifferent colors cannot be ascertained and programmed (learned) in agiven distance range in which only the docking opening of the colorvalve of a single color can be located. It is also checked that in eachcase between the two detected color positions the intended distance ismaintained within a given tolerance limit in order to prevent the systemfrom skipping a color position for example when ascertaining the nominalvalues. It can then also advantageously be checked that the colorpositions are “learned” in the logical sequence of the colors (1, 2, 3,. . . ).

The positioning and programming according to the exemplary illustrationsis also suitable for other docking color changers including rotary colorchangers with rotatable docking inlets, and is also not necessarilylimited to robots suitable for interior and exterior painting.

FIGS. 9A to 9D show different operating states of the exemplary paintingrobot 1 in the context of a so-called “push-out mode”, wherein thedifferent operating states are shown in FIG. 10 in the form of aflowchart.

A normal painting mode will first be described below with reference toFIG. 9A.

In the normal painting mode shown in FIG. 9A, the docking carriage 16 isdocked onto the color bar 12 by means of a first docking inlet and apaint having the desired color is extracted from the color bar 12 via acolor feed line 13.1 and a color valve F1.

The paint extracted from the color bar 12 may then be passed via aseparating valve FGV/F into a common color line 25, wherein the commoncolor line 25 leads via the metering pump 10 to the rotary atomizer 7which applies the supplied paint when the main needle valve HN is open.

The operating state of the painting robot shown in FIG. 9B will now bedescribed below.

Firstly, in this operating state, the paint located in the common colorline 25 is pushed out of the common color line 25, for which reason thisoperating state is also known as the “push-out mode”. In this operatingstate, the color valve F1 is closed, so that the color bar 12 does notdispense any paint to the docking carriage 16.

Instead, a flushing agent (e.g., a thinner for the paint used) isintroduced via a flushing agent feed line 26 and a flushing agent valveV/PO into the common color line 25, wherein the flushing agent serves asa displacement medium and pushes the paint remaining in the common colorline 25 out of the common color line 25 via the rotary atomizer 7. Inthis case, the paint pushed out via the rotary atomizer 7 can at firststill be used for painting, but the painting mode must be adjusted ingood time before the flushing agent introduced via the flushing agentfeed line 26 exits from the rotary atomizer 7.

In this operating state, the separating valve FGV/F is closed and thusseparates the common color line 25 from the docking point on the colorbar 12, which allows a flushing of the docking point.

To this end, flushing agent is introduced into the docking carriage 16via a flushing agent feed line 27 and a flushing agent valve V, whereinthe flushing agent reaches as far as the docking points on the color bar12 and thus flushes said docking points. Finally, the introducedflushing agent is then fed back via a return valve RF2 and a return line28.

In this example, therefore, two separate flushing circuits may beprovided which allow a simultaneous flushing of the common color line 25and of the docking points.

The first flushing circuit leads from the flushing agent feed line 27via the flushing agent valve V and the valve V/PL to the docking pointsof the color bar 12 and finally via the return valve RF2 into the returnline 28.

By contrast, the second flushing circuit leads from the flushing agentfeed line 26 via the flushing agent valve V/PO into the common colorline 25, from where the first flushing circuit runs via the meteringpump 10 into the rotary atomizer 7 and through the main needle valve HN.

Furthermore, in this operating state, pulsed air is introduced via anon-return valve RV and a pulsed air valve PL in order to improve theflushing effect.

As shown in the flowchart in FIG. 10 (to the right next to “FIG. 9B”),the docking interface is not flushed before or after the line leadingthrough the atomizer but rather in parallel therewith, that is to saysimultaneously, in order to avoid delays in operation.

The operating state shown in FIG. 9C will now be explained below.

On the one hand, as is shown and after a corresponding displacement, thedocking carriage 16 in this operating state docks with a second dockinginlet (instead of with its first docking inlet as in FIGS. 9A and 9B)onto another docking point of the color bar 12 in order to extract adifferently colored paint. To this end, the docking carriage 16 isdisplaced by the servo-pneumatic linear drive 17 relative to the colorbar 12 in the direction of the arrow, wherein the docking carriage 16 inthe drawing docks onto the docking point of a color valve F2 which issupplied with a paint of a given color via a color feed line 13.2.

On the other hand, a flushing of the rotary atomizer 7 and of themetering pump 10 takes place in this operating state. To this end,flushing agent is introduced via the flushing agent feed line 27 and theflushing agent valve V, said flushing agent passing via an open valveV1/PL and the likewise open color valve into the common color line 25.From there, the introduced flushing agent reaches the rotary atomizer 7and is then returned via the main needle valve HN and a return valveRF1, which is arranged in the rotary atomizer 7, and a return line 29.

Furthermore, in this operating state, pulsed air is introduced via thenon-return valve RV and the pulsed air valve PL in order to improve theflushing effect.

The operating state of the painting robot 1 shown in FIG. 9D will now beexplained, in which the new paint is supplied. In this case, the desiredpaint reaches the rotary atomizer 7 from the color feed line 13.2 viathe open color valve F2 and the open separating valve FGV/F, the mainneedle valve HN initially still being closed. At the end of thisoperating state, the rotary atomizer 7 is then able to apply the newpaint.

FIGS. 11A to 11E show different operating states in a modified exampleof embodiment of the painting robot which allows a so-called “reflowmode”, in which the paint remaining in the common color line 25 in theevent of a color change is pushed back into the associated color feedline 13.1 or 13.2 in order to allow reuse.

The operating state shown in FIG. 11A will first be explained below,which may be associated with operation during a normal painting mode. Inthis operating state, paint passes via the color feed line 13.1, thecolor valve F1, a first docking inlet of the docking carriage 16, theseparating valve FGV/F and the common color line 25 to the rotaryatomizer 7, which applies the supplied paint when the main needle valveHN is open.

The operating state shown in FIG. 11B will now be explained, in whichthe paint located in the common color line 25 between the color changer8 and the rotary atomizer 7 in the event of a color change is pushedback into the associated color feed line 13.1.

To this end, use is made of a flushing agent metering means 30 in theform of the illustrated reflow cylinder, which can be filled withflushing agent on the inlet side via a flushing agent feed line 31 and aflushing agent valve AV2/V. As described above, a “metering means” mayinclude a device intended to convey a predefined volume of liquid (dose)but, in contrast to the metering pumps used for coating material, doesnot have to produce a defined volume flow per unit of time.

On the outlet side, the flushing agent metering means 30 is connected tothe common color line 25 via a flushing agent valve AV1/V in the rotaryatomizer 7 upstream of the main needle valve HN.

In the so-called “reflow mode”, the flushing agent metering means 30pushes the flushing agent located therein via the flushing agent valveAV1/V into the common color line 25, wherein the flushing agentintroduced serves as a displacement medium and pushes back into theassociated color feed line 13.1, via the separating valve FGV/F and thecolor valve F1, the paint located in the common color line 25, whichallows a subsequent reuse of the paint that has been pushed back.

The operating state shown in FIG. 11C will now be explained below, inwhich the metering pump 10 and the rotary atomizer 7 are flushed.

To this end, flushing agent is introduced from the flushing agent feedline 27 via the flushing agent valve V and the valve V1/PL into thecommon color line 25, wherein the flushing agent passes via the mainneedle valve HN of the rotary atomizer 7 and the return valve RF1 intothe return line 29. Furthermore, in this operating state, pulsed air isintroduced via the non-return valve RV and the pulsed air valve PL inorder to improve the flushing effect.

The operating state shown in FIG. 11D will now be explained below, inwhich the docking carriage 16 is flushed as far as the docking points onthe color bar 12.

To this end, flushing agent may be introduced from the flushing agentfeed line 27 via the flushing agent valve V and the valve V/PL, saidflushing agent reaching as far as the docking points of the color bar 12and thus flushing the latter. The introduced flushing agent is thenpassed via the return valve RF2 into the return line 28.

Furthermore, also during the flushing of the docking carriage 16, pulsedair is introduced via the non-return valve RV and the pulsed air valvePL in order to improve the flushing effect.

The operating state shown in FIG. 11E will now be explained below.

On the one hand, as is shown and after a corresponding displacement, thedocking carriage 16 in this operating state docks with its seconddocking inlet (instead of the aforementioned first docking inlet) ontoanother docking point of the color bar 12 in order to extract a painthaving a different color.

On the other hand, the new paint is pushed in this operating state.Here, the paint passes from the color feed line 13.2 via the color valveF2 and the separating valve FGV/F to the rotary atomizer 7, where thenew paint is then available at the main needle valve HN, which isinitially still closed. Following this supply of the new paint, therotary atomizer 7 can then apply the new paint.

For a further time saving during a color change, the valve systemsdescribed above (FIGS. 9-12) for the push-out and reflow modes can beexpanded to an A/B system in which two separate color lines lead inparallel from the docking carriage 16 into the atomizer 7.

The main details of the A/B push-out system can be seen in the drawingsstarting from FIG. 13A. Accordingly, the docking carriage 16, which canbe displaced along the color bar 12 comprising the color valves F1, F2,etc., may have two docking inlets 40 and 41 which can be selectivelyconnected to color valves of the color bar 12 and of which only one orthe other is connected to one of the color valves in the color bar 12depending on the position of the docking carriage, while the respectiveother docking inlet may be sealed off for example by the color bar (asin the examples shown in FIGS. 9-12). The four illustrated valves,namely the return valve RLF, the color valve LFA of the A-branch, thecolor valve LFB of the B-branch and the flushing valve LSV, may beconnected in parallel with one another to the two docking inlets in thedocking carriage 16. From the color valve LFA, the color line 25A of theA-branch leads via the metering pump 10A into the atomizer 7 and thereinto a color valve FA arranged within the atomizer upstream of the mainneedle valve HN. In parallel therewith, the color line 25B of theB-branch leads from the color valve LFB via the metering pump 10B intothe atomizer and therein to a color valve FB arranged within theatomizer upstream of the main needle valve HN and parallel to the valveFA.

The docking carriage 16 furthermore may contain the two illustratedpush-out valves LPOA and LPOB, of which the valve LPOA is connectedwithin the docking carriage to the line 25A leading from the valve LFAto the metering pump 10A and similarly the valve LPOB is connected tothe line 25B. At their respective inlet, the valves LPOA and LPOB areconnected to a line 26PO leading into the docking carriage for flushingagent (thinner) which serves as the pushing agent for the push-out mode.In addition, the docking carriage contains the two illustrated flushingvalves LVPLA and LVPLB, of which, in a manner similar to the valves POAand POB, one is connected to the line 25A and the other is connected tothe line 25B, and which are connected on the inlet side via the line26V/PL to the external valves V and PL for flushing agent (thinner) andpulsed air.

Located in the atomizer 7 are further valves PL′ and V for pulsed airand thinner which are connected upstream of the main needle valve HN inparallel with the aforementioned valves FA and FB and can be supplied onthe inlet side by corresponding lines (not shown) which lead into theatomizer. Furthermore, the atomizer contains the two illustrated returnvalves RFA and RFB which, as is shown, are connected between the inletside of the valve FA and FB respectively and the return line 29 commonto said valves.

In the operating state shown in FIG. 13B, in which (only) the valves F1,LFA, FA and HN are open and the docking inlet 40 of the docking carriage16 is docked onto the valve F1 of the color bar 12, the relevant paintflows through these valves into the bell cup of the atomizer 7. Paintingtherefore may generally take place through the A-branch.

In the operating state shown in FIG. 13C, (only) the valves LSV, LRF,POA, V, PL and also the valves FA and HN are open, while the previouslydocked color valve LFA is now blocked. In this operating state, residualpaint still located in the line 25A is pushed toward the metering pump10A by the pushing agent (thinner) from the line 26PO via the open valvePOA and is conveyed by said metering pump into the bell cup in order tobe used for the final painting according to the push-out principle knownper se. This operating state lasts until the residual quantity of paint(precisely determined beforehand in terms of quantity and time) isconsumed. In parallel with this and at the same time, the interface ofthe docking carriage 16 with the two docking inlets 40 and 41 is flushedwith the flushing agent coming from the line 26V/PL, i.e. with thinnerand pulsed air. The flushing agent can flow off through the open returnvalve LRF.

In the operating state shown in FIG. 13D, the flushing process is ended(valves LSV and LRF closed), while the push-out mode through theA-branch is continued and at the same time the docking carriage 16 ispushed with its second docking inlet 41 onto the color valve F2 of thecolor bar 12.

Also in the operating state shown in FIG. 13E, the push-out mode usingthe color from the color valve F1 through the A-branch is continued. Inparallel with this and at the same time, however, the next color mayalready be supplied via the inlet 41 docked onto the color valve F2 forthe next color through the open valve LFB through the B-branch, i.e. theline 25B and the metering pump 10B, until it reaches the color valve FBof the atomizer, which is still closed, wherein the line can be ventedvia the valve RFB.

In the operating state shown in FIG. 13F, the push-out mode is ended(valve POA closed) so that the atomizer with its bell cup can be flushedvia its open valves V′ and PL′ and the main needle valve HN.

In the operating state shown in FIG. 13G, painting takes place with thenew color through the B-branch and the color valve FB of the atomizer,which is now open, while in parallel therewith and at the same time viathe open valve LVPLA the line 25A including the metering pump 10A as faras the closed color valve FA of the atomizer is flushed with theflushing agent coming from the line 26V/PL, which flows off through theopen return valve RFA. Consequently, the A-branch is now immediatelyavailable again for the next color.

FIG. 13H shows a typical example of the temporal sequence of thedescribed push-out A/B mode. At “start”, the push-out mode in theA-branch described with reference to FIG. 13C, etc. and the simultaneousflushing of the interface of the docking carriage begin. As can be seenfrom this figure, the color change time in the example underconsideration is only approximately 6 seconds.

Further details of the A/B reflow system can be seen in the drawingsstarting from FIG. 14A. With regard to the arrangement of the valvesLRF, LFA, LFB, LSV, V and PL and also LVPLA and LVPLB in the dockingcarriage 16, the metering pumps 10A and 10B and the valves FA, FB, PL′,V′ and also RFA and RFB located in the atomizer 7, the reflow system cancorrespond to the A/B push-out system. The same applies to otherdetails.

By contrast, naturally the valves POA and POB of the push-out system areomitted, while on the other hand the additional reflow valve V_(Reflow)may be arranged upstream of the main needle valve HN in parallel withthe valves FA to V′ in the atomizer and may be arranged for exampleoutside the atomizer in the robot arm of the reflow cylinder or flushingagent metering means 30 having the flushing agent valves AV2/V alreadydescribed in the examples of embodiments shown in FIG. 11A, etc. Theflushing agent metering means 30 is connected to the reflow valveR_(Reflow) via the reflow line LR.

In the operating state shown in FIG. 14B, in which (only) the valves F1,LFA, FA and HN are open, painting takes place as in FIG. 13B using thepaint flowing out of the color valve F1 in the A-branch.

In the operating state shown in FIG. 14C, the painting mode is ended byclosing the main needle valve HN, and the reflow valve V_(Reflow) isopened while the valve FA is still open. With the flushing agent(thinner) serving as the reflow pushing means, the flushing agentmetering means 30 pushes the paint still located in the line 25A backthrough the valve FA to the metering pump 25A, which conveys the paintwith the opposite direction of rotation through the open valves LFA andF1 back into the color supply system (reflow).

As soon as reflow through the color valve F1 of the color bar 12 isended and this valve is closed again, the interfaces of the dockingcarriage 16 comprising the docking inlets 40 and 41 can be flushed asshown in FIG. 14D via the open valves LSV and LRF, while at the sametime the bell cup can be flushed via the valves V′ and PL′ of theatomizer and via the main needle valve HN.

Now, as shown in FIG. 14E, by displacing the docking carriage 16, thesecond docking inlet 41 thereof is connected to the color valve F2 forthe next color. In parallel with this and at the same time, while theflushing of the bell cup continues, the color line 25A of the atomizercan be flushed, namely with the thinner coming through the open valveLVPLA and conveyed by the metering pump 10A, said thinner then flowingoff through the open return valve RFA and the line 29.

Still during the flushing of the line 25A and as shown in FIG. 14F, thenew color is supplied from the color valve F2 through the valve LFB intothe line 25B and to just before the color valve FB of the atomizer,wherein, in a manner similar to FIG. 13E, ventilation through the valveRFB is possible. At the same time, the reflow cylinder of the flushingagent metering means 30 can be topped up through the valve AV2/V.

In the operating state shown in FIG. 14G, painting takes place using thenew color conveyed from the color valve F2 through the B-branch, i.e.the line 25B, into the bell cup. In parallel therewith and at the sametime, the flushing of the A-branch as shown in FIG. 14F can be continuedand then ended.

FIG. 14H shows a typical example of the temporal sequence of thedescribed reflow A/B mode. At “start”, the docking movement of thedocking carriage 16 described with reference to FIG. 14E begins untilthe inlet 41 is connected to the color valve F2. As can be seen fromthis figure, the color change time in this example is approximately 10seconds.

If the atomizer 7 is to be flushed through the open return valve RFA,e.g. with the color valve FA closed (FIG. 13G and FIG. 14E), the closedcolor valve should to the greatest possible extent also be flushed asfar as its valve seat. The exemplary structural unit shown schematicallyin FIG. 15 and consisting of the color valve FA and the return valve RFAis suitable for this. In this example, both valves are designed asautomatically controlled needle valves of a type generally known per sefrom painting installations (which may also be suitable for the othervalve functions shown in the various drawings, usually with theexception of HN). As is known, such valves may have a tubular housingpart 50 with a cylindrical/conical interior, through which the valveneedle (not shown) extends as far as the valve seat formed in the outerend of the housing part 50, said valve needle being displaceable bymeans of an e.g. pneumatic and pneumatically controlled drive in theadjoining housing part 51. The line 52, through which the color F to becontrolled is conveyed into the color valve FA under consideration inthe illustrated example, is connected to the interior of the housingpart 50 at a point located axially opposite said valve seat. In the openstate of the valve FA, the color flows on the other side of the valveseat into the outlet line 53.

The return valve RFA may correspond in design terms to the color valveFA, i.e. may have its valve seat in the end of its tubular housing part60 and the connection line 62 opposite thereto. According to the drawingand the exemplary illustrations, however, the end of the housing part60, which is conical in this example, opens on the other side of itsvalve seat into the corresponding housing part 50 of the color valve FAso that, when the return valve RFA is open, the two connection lines 52and 62 are connected to one another by the physically adjoininginteriors of the two valves. Therefore, when the color valve FA isclosed and the return valve RFA is opened, firstly residual paint andthen the flushing agent can flow through the connection line 52 into theinterior of the valve FA in order to flush the illustrated valve unitand from there can flow off through the return valve RFA and the line 62thereof, as shown by the arrow RF.

A similar valve arrangement may advantageously be provided for thevalves RFB and FB of the B-branch of the above-described A/B systems.Instead of the special valve unit shown schematically in FIG. 15,constructions or arrangements are also conceivable in which the valveseat of the return valve is not located in or on the interior of thecolor valve but rather outside the latter and is connected to the colorvalve via a suitable line. Furthermore, other known types of valve canbe selected both for the above examples of embodiments and also for theexamples of embodiments described below, provided that they are suitablefor the described purpose.

As has already been mentioned above (in relation to FIG. 5), the colorvalves 14 may be inserted in the side face of the color bar locatedopposite the docking points in at least two rows arranged one above theother and parallel to one another in the longitudinal direction of thecolor bar 12, so that the overall length of the color bar 12 isaccordingly reduced. One advantageous example of this arrangement isshown in partially simplified form in FIG. 16, where it is also possibleto see on the upper side of the color bar 12 the plug-in nipples 22likewise already mentioned (in relation to FIGS. 7 and 8) which serve asa color connection for a respective color valve. As shown in thedrawing, the plug-in nipples 22 are inserted into the end faces 65 onthe upper side of the color bar 12, said end faces being angled in themanner of a roof and being visible also in FIG. 4, so that their axesperpendicular to the angled end faces 65 are likewise inclined at anangle relative to the longitudinal direction of the color bar 12 and forexample the clamping screws 24 (FIGS. 7 and 8) can be inserted into therespectively adjacent, oppositely angled end faces. The plug-in nipples22 may also be arranged respectively next to one another in two rowsparallel to the longitudinal direction, of which only the front row ofplug-in nipples in the drawing can be seen in FIG. 16. In the region ofthe side face 66 of the color bar 12 which adjoins the underside of thecolor bar opposite the paint connections, the first row of color valves14 extends parallel to the longitudinal direction of the color bar asshown in the drawing. The second row of color valves 14′ is inserted inthe adjoining region of the side face 66 in the direction of the paintconnections, wherein the valves 14 and 14′ are offset relative to oneanother in the longitudinal direction according to the drawing. As aresult, the bores of the two rows which are generally necessary forinserting the color valves may be at a smaller vertical distance fromone another in the direction vertical to the longitudinal direction, sothat a particularly compact structure and small height of the color bar12 is obtained, as may be desirable and advantageous according to theexemplary illustrations to provide a robot arm that is as flat aspossible for the reasons mentioned above.

Since the number of connectable colors and thus of the required colorvalves 14 and 14′ may differ from case to case, but in each casecomponents of the color changer which are as uniform as possible shouldbe used, the color bar 12 may have a modular structure which can beextended or reduced in size in a desired and simple manner with regardto the connectable colors. In the example shown in FIG. 16, the colorbar 12 consists of a desired number (here 9) of securely but detachablyassembled modules of the type shown schematically for illustrationpurposes in FIG. 17. As can be seen therefrom, each module 67 containstwo color valves 14 and 14′, the central axes of which are at a verticaldistance A, i.e. measured perpendicular to the longitudinal direction ofthe color bar 12 (and consequently to the direction of displacement ofthe docking carriage 16), and have a valve offset VV measured parallelto the longitudinal direction, wherein A is smaller than the actualmutual spacing between the valve axes and in the illustrated example isonly slightly larger than the diameter of the valve bore in the plane ofthe end face 66, while VV may be approximately the same as or, as shownin the drawing, somewhat larger than half the diameter of the valvebore. One of the two plug-in color connection nipples 22 of the module67 can be seen on the aforementioned angled end face 65.

So that the horizontal length of the color bar 12, i.e. the lengthmeasured in its longitudinal direction, is not increased by thehorizontally offset arrangement of the color valves, each module 67 hasthe illustrated curved profile of its transverse faces 68 and 69extending generally perpendicularly to the side face 66. Accordingly,the transverse face 68 on one side of the module runs from the angledend face 65 initially vertically along the upper color valve 14′, inorder then to curve inward, approximately following the circular shapethereof, until it comes into the vicinity of the lower color valve 14,along which it then runs vertically again as far as the underside of thecolor bar 12. The transverse face 69 has a curve profile parallel tothis, so that the transverse faces 68 and 69 of adjacent modules 67precisely fit onto and into one another, as can be seen in FIG. 16. Thedescribed shape of the modules 67 has the advantage that, despite thehorizontal valve offset VV in the longitudinal direction of the colorbar 12, they take up no more space than a module which contains just onesingle color valve 14. Within the overall length of the color bar 12,the individual modules are wider than the diameter of a valve bore onthe outside of the color bar only by the necessary wall thickness of themodule body.

FIG. 18 shows the rear side of the modular color bar 12 of FIG. 16, i.e.the docking side thereof with the openings of the docking points 15 and15′ arranged in two rows. These openings have the same axis as theneedle axes or central axes of the associated color valves 14 and 14′and are thus likewise offset from one another by the values A and VV(FIG. 17). Furthermore, it can be seen that in each row of color valvesand docking points 15 and 15′ the mutual spacing between the axes ofadjacent valves or docking points may in each case be equal to twice thevalve offset VV. In other words, in each case one color valve of one rowis located in the middle between two color valves of the other row inthe longitudinal direction of the color bar 12. Also shown is the row ofdocking points 71 for the control air of the color valves, which isparallel to the rows of docking points 15 and 15′ and which is locatedin this example between the upper docking points 15′ and the upper sideof the color bar. As has already been described, each color valve 14 and14′ has its own docking position for the docking carriage 16, which isin each case defined by one of the positioning and centering bushings 70for the centering pins (not shown) mentioned above, said bushings beingshown at the lower edge of the color bar 12. For the sake ofsimplification, the guide construction (groove 18 in FIGS. 4 and 6) forthe docking carriage is omitted in FIG. 18.

Also shown in FIG. 18 are holding parts 72 and 73 at both ends of thecolor bar 12 which serve for holding and fixing the color bar in therobot arm 5 (FIGS. 1-3) and for this purpose are releasably attached toa respective end module 67. According to the drawing, the holding parts72 and 73 have end faces 74 and 75 which face toward the end modules andhave the curve shape of one or the other transverse faces 68 or 69 ofthe modules 67, so that the transverse faces of the latter fit preciselyonto and into the relevant end faces 74 and 75 of the holding parts.

In the example shown in FIGS. 16-18, the color lines 13 (FIG. 1) maylead via a respective plug-in connecting nipple 22 in each case as astub line to the associated color valve 14 or 14′. In other cases, onthe other hand, a constant circulation of color should take place fromthe color source (usually via annular lines) to the relevant valve, forexample directly to the valve seat thereof, and from there via anadditional line back to the color source, in order to avoid any possibleseparation of the individual color components which may be possibleunder some circumstances in stub lines. To this end, each module of thecolor bar 12 requires twice the number of color connections, i.e. fourinstead of two plug-in nipples 22 in the example shown in FIGS. 16-18for two colors. One example of embodiment of a particularly compact andspace-saving module 77 of the color bar 12 for two colors and colorcirculation is shown in FIG. 19. The arrangement of the two color valves14 and 14′ and the curve shape of the transverse face 68 may correspondto the module 67 described above. By contrast, according to the drawing,three plug-in nipples 22 are arranged next to one another as three ofthe four necessary connections for respective color lines on the upperangled end face 85 in the drawing, which corresponds to the end face 65of the module 67, while the necessary fourth plug-in nipple is placedfor space reasons in the vicinity of a different location where itneither hinders the described well-fitting assembly of the modules norincreases the height and length of the color bar 12. One locationsuitable for this purpose, for example, is a face 81 of a shoulder 82which protrudes from the side face 66 above the upper color valve 14′ inthe drawing transversely to the longitudinal direction of the color bar12, which face 81 for example adjoins at an angle the transverse face 68as shown in FIG. 19. The fourth plug-in nipple 22 inserted in the face81 therefore projects laterally outward at an angle from a corner of themodule body in this exemplary illustration.

FIG. 20 shows a rear side or docking side of the module according toFIG. 19 and the guide construction corresponding for example to FIG. 6Bwith the groove 18 for the docking carriage 16 (FIG. 5). This guideconstruction includes the surface elements 86 and 87 which delimit thegroove on its two (upper and lower) sides and which contain thedescribed openings of the color docking points 15 and of the control airdocking points 71 and may be formed in one piece with the module body.According to the drawing, one (upper) surface element 86 has on its edgeadjoining the transverse face 69 of the module a flat, round projection90 which protrudes parallel to the side face of the module and fitsprecisely into a likewise flat, round recess 91 of the surface element86 on the opposite edge of said module and thus also into thecorresponding recess 91 of an adjacent module fitted onto the transverseface 69. Similarly, the other (lower) surface element 87 may have at itstwo edges a rounded protruding projection 92 and a matching recess 93,wherein the projections 90 and 92 may be located on opposite edges ofthe side face of the module 77. This guide construction, which can alsobe seen on the rear side of the diagram in FIG. 19, may improve theprecision with which adjacent modules fit together.

One advantageous and space-saving valve arrangement of a module for twocolors, which allows the desired color circulation as far as therespective valve seat and thus as far as the docking point in thedescribed example of embodiment, is shown partially schematically and insimplified form in FIG. 21. The two color valves 14 and 14′ may be theneedle valves of the conventional type already described in relation toFIG. 15 which are used in the module shown in FIG. 19. A first forwardflow pipe 113 leads from a connecting nipple 122, to which an externalfeed line (one of the lines 13 in FIG. 1) for a first color isconnected, into the tubular housing part 114 of the first color valve14, which contains the valve seat. From the housing part 114, a backwardflow pipe 115 then leads to a second connecting nipple 123, to which anexternal return line (which may likewise be one of the lines 13 inFIG. 1) for the first color is connected. Via corresponding forward andbackward flow pipes 113′ and 115′, the tubular housing part 114′ of thesecond color valve 114′ of the module under consideration may also beconnected to corresponding connecting nipples 122′ and 123′ for thesecond color. The connecting nipples 122, 122′, 123 and 123′ may be thefour plug-in nipples 22 shown in FIG. 19. For the drive control of thecolor valves 14 and 14′, a respective further pipe 117 or 117′ for therespective control air for switching the valve is connected to thewidened housing part 116 or 116′ thereof. The control air can besupplied through the aforementioned docking points 71 (FIGS. 18 and 20).The spatial arrangement of the color valves and of the variousconnections for color and control air may correspond to the module shownin FIGS. 19 and 20. The described pipes may advantageously be embodiedby generally simple and substantially straight (angled relative to oneanother where necessary) bores within the module body and/or pipeelements inserted in these bores. The module body may be made in onepiece for example from metal or another suitable material. Instead ofthe straight bores shown in the drawing, curved guide paths may also beprovided if desired, wherein the module body may be produced for exampleby a generative or so-called rapid prototyping method, e.g., asdescribed in DE 10 2008 047 118.6, or by a similar known generativemethod, which is also suitable for metal bodies.

Instead of the example of a module 67 for two colors, both modules forjust one color and also modules for three or more colors with as manycolor valves with or without color circulation may be provided for thecolor bar of the described docking color changer. By way of example, amodule for four or six colors would simply have the shape of two orrespectively three adjacent modules 67 or 77 (FIGS. 16-20). By contrast,a module for three or five colors for example would differ from themodules 67 and 77 by a different arrangement of the paint connectionnipples and also by the fact that the curves of the two transverse facesof the module (corresponding to 68 and 69) would not run parallel to oneanother but rather would run in the form of a mirror image relative toone another, and the side face of the modules would therefore have awider and a narrower region compared to modules for an even number ofcolor valves.

In so far as it has been described until now, the docking color changermay be used in particular for frequently required standard colors fromthe annular lines customary in painting installations of the type underconsideration here. However, it can be extended in a simple manner alsoto the connection of, for example, rarely required special colors, forexample by adding at least one special module for special colors asshown in FIG. 22. This module for special colors, which is denoted by127, is seated here by way of example between two modules 77 of the typedescribed above and shown in FIGS. 19 and 20, with which it coincideswith regard to the curve shape of its transverse faces (corresponding to68 and 69) and its surface elements (corresponding to 86 and 87) withthe described projections and recesses (corresponding to 90-93), so thatit fits precisely onto and into the transverse faces of the modules 77.On the docking side of the module 127 which can be seen in FIG. 22,there is located in the row of upper docking points 15′ a docking point15″ onto which the inlet of the docking carriage 16 intended for thisrow can dock, as will be described below (FIG. 23A).

The special color supply may generally be intended to take place throughone or more color tubes which are pigged in any manner that isconvenient, through which the colored paint is conveyed by pigs whichcan in turn be driven by a pushing means such as compressed air orthinning fluid (e.g., as described in EP 1362641 B1, EP 1362642 B1,etc.). The pigging tube (not shown in FIG. 22) is connected at theillustrated arrow to, for example, a cylindrical connection body 130which may be constructed as a pigging station. Arranged next to theconnection body 130 is a further e.g. tubular connection body 132 forcompressed air, which may contain a non-return valve (RV in FIG. 23A).Moreover, a further connection body 133 for a return line (136 in FIG.23A) is seated next to the connection body 132. As shown in the drawing,the three connection bodies 130, 132 and 133 may be inserted next to oneanother, in a manner similar to the connecting nipples 22 of thestandard color modules 77, into an end face 135 of the module 127 whichis angled in a roof-like manner, so that the central axes thereof, in amanner similar to the three connecting nipples 22 arranged next to oneanother, are inclined in planes parallel to the longitudinal directionof the color bar at an angle relative to this longitudinal direction. Asa result, a small connection height is also obtained for the module 127,as is desirable for a flat color changer which is to be used forinstallation in a robot arm for interior painting.

In the illustrated example, the module 127 is twice as wide in thelongitudinal direction of the color bar as the modules 77 for standardcolors. A plurality of modules 127 for special colors may also beinstalled in the illustrated manner in the color bar. Furthermore, apigging path common to a plurality of special colors may be provided,for example as described in EP 1522348 A2.

In order to explain the mode of operation, the valve scheme of thespecial color supply is shown in partially simplified form in FIG. 23A.Accordingly, the color bar 12 contains within the above-described module127 a color valve F, shown as a directional control valve, whichcontrollably connects the pigging tube 135, which is connected to theconnection body 130 (FIG. 22), to the docking point 15″ of the module127 and to an inlet of the return valve RF, to the outlet of which thereturn line 136 is connected via the aforementioned connection body 133.Also connected to the inlet of the return valve RF is the outlet of acompressed air valve PLM, the inlet of which is connected to acompressed air line 137 via the non-return valve RV in theaforementioned connection body 132. As in the examples of embodimentsdescribed further above, F1 and Fn denote the color valves for standardcolors provided in the color bar 12.

FIG. 23B is a somewhat more detailed illustration of the valvearrangement within the module 127.

During operation, firstly the special color may be supplied from thepigging tube 135 through the color valve F, which is open in thedirection of the return valve RF, and through the initially likewiseopen return valve RF into the return line 136, so that the special colorcan then be supplied without air to the docking point 15″. When thespecial color reaches the return line 136, which is reported by a paintsensor ZFS, the valve RF can be closed and the color valve F can beopened toward the docking point 15″ and the docked inlet 40 of thedocking carriage 16. The special color can flow for example into thedocking carriage 16, until the pig conveying the special color throughthe pigging tube 135 reaches the connection body 130. However, a mode ofoperation is also possible in which the color is then further conveyedpast the pig, e.g., in any known manner that is convenient. In any case,after the end of the application process, the pig can be pushed backthrough the pigging tube 135 and in the process can push the colorresidue located therein back to the color source, so that no paintlosses are obtained also for the special color. The pig can be pushedback by the compressed air introduced through the valve PLM with thevalve RF closed and the docking point blocked.

Thinner and/or compressed air from the docking carriage may be used toflush the valve arrangement of the module 127 (possibly also to pushback the pig). Another possibility which is advantageous at present liesin conveying a flushing agent, such as e g thinning fluid, through thepigging tube 135 into the module 127, from where it can flow off throughthe return line 136. Furthermore, pulsed air may also be suppliedthrough the valve PLM in order to flush the valve arrangement.

The valve arrangement on the atomizer side of the color changer maycorrespond to an example of embodiment described above for the standardcolors, for example the arrangement described with reference to FIG. 9A,etc., wherein the valves LRF, LF, LSV, LVPL and LPO are functionallyidentical to the valves RF2, FGV/F, V/PL, V1/PL and V/PO in FIG. 13. Thesame applies to the valves V, PL, HN and RF1. As can be seen, the valvearrangement on the atomizer side in FIG. 23A substantially alsocorresponds to the arrangement described with reference to FIG. 13A,etc. when it is reduced to just one color line 25 instead of the A/Bsystem shown in FIG. 13, although the latter can likewise be used here.

The exemplary illustrations include different aspects, such as forexample the color changer, the new type of connection structure for thecolor lines, the “push-out mode” and the “reflow mode”, optionally withthe described A/B systems, which may also be suitable for differenttypes of docking color changers, including those with rotatable dockingparts, and the separate flushing circuits. The same applies to theexemplary valve arrangement which was described with reference to FIG.15 and which may also be advantageous for other purposes in a paintinginstallation. It must therefore be mentioned that the individual aspectsof the exemplary illustrations are notable independently of one another.

One aspect which is also worthy of protection must also be seen inparticular in using for the interior painting of bodies a painting robotwhich is mounted at a raised height, for example in a stationaryposition or on a displacement rail as described in EP 1 609 532 A1, ashas already been mentioned above. For example, the pivot axis of itsdistal arm (“axis 3”) during painting may be located in the verticaldirection below the pivot axis of the upper arm (“axis 2”), known as“arm 1”, which is in the vertical axis of rotation (“axis 1”) of therobot (known per se as “elbow down”). In this position, during interiorpainting, the distal arm can be introduced e.g. at least approximatelyhorizontally into the interior spaces of the body better than in theposition customary until now in which the “axis 3” was above the “axis2” in the vertical direction, so that the risk of collisions can beavoided even when the application technology including the color changerand possibly metering pumps, paint pressure regulators, etc. areinstalled on or in the distal arm. As already mentioned in theintroduction, one advantageous installation of the applicationtechnology in the “arm 2”, according to the exemplary illustrations, hasthe important advantage of reduced color change losses. In this case, itmay be advantageous if the pivot axis bearing of the upper arm (“axis2”) is not located conventionally above the robot base but rathervertically below the robot base, so as to obtain correspondinglyreversed kinematics. For the painting of other, in particular outerfaces of the body, the robot arms can also be pivoted into the reverseposition, in which the “axis 3” is located above the “axis 2”. The “axis2” may be located below the displacement rail of the robot.

The exemplary illustrations are not limited to the specific examplesillustrated above. Rather, a plurality of variations and alterations arepossible that also make use of the ideas described herein, and thereforefall within the scope of protection. Reference in the specification to“one example,” “an example,” “one embodiment,” or “an embodiment” meansthat a particular feature, structure, or characteristic described inconnection with the example is included in at least one example. Thephrase “in one example” in various places in the specification does notnecessarily refer to the same example each time it appears.

With regard to the processes, systems, methods, heuristics, etc.described herein, it should be understood that, although the steps ofsuch processes, etc. have been described as occurring according to acertain ordered sequence, such processes could be practiced with thedescribed steps performed in an order other than the order describedherein. It further should be understood that certain steps could beperformed simultaneously, that other steps could be added, or thatcertain steps described herein could be omitted. In other words, thedescriptions of processes herein are provided for the purpose ofillustrating certain embodiments, and should in no way be construed soas to limit the claimed invention.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be evident uponreading the above description. The scope of the invention should bedetermined, not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur in the artsdiscussed herein, and that the disclosed systems and methods will beincorporated into such future embodiments. In sum, it should beunderstood that the invention is capable of modification and variationand is limited only by the following claims.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose skilled in the art unless an explicit indication to the contraryis made herein. In particular, use of the singular articles such as “a,”“the,” “the,” etc. should be read to recite one or more of the indicatedelements unless a claim recites an explicit limitation to the contrary.

The invention claimed is:
 1. A painting robot adapted for painting motorvehicle bodies having outer faces to be painted on the outside of themotor vehicle bodies and inner faces to be painted in the interior ofthe motor vehicle bodies by an atomizer guided by the painting robot,wherein the painting robot is adapted both for painting the outer facesand for painting the inner faces of the motor vehicle bodies, thepainting robot comprising: at least one robot arm configured tospatially position the atomizer, the at least one robot arm including adistal arm; and a color changer mounted on the distal arm, the colorchanger including: a plurality of color feed lines on an inlet side; acommon color line on an outlet side configured to forward paint selectedby the color changer to the atomizer; a color bar comprising a pluralityof docking points supplied by the color feed lines, and a colorextractor configured to selectively dock onto one of the docking pointsof the color bar and, while docked to the color bar, extract paint froman associated color feed line and supply the extracted paint to thecommon color line.
 2. The painting robot according to claim 1, whereinthe motor vehicle bodies to be painted have body openings, and thedistal robot arm has a width in a direction measured transversely to itslongitudinal axis that allows the atomizer to be positioned in theinterior of the motor vehicle bodies through the body openings.
 3. Thepainting robot according to claim 1, wherein a) there is arranged ineach of the color feed lines a color control device which selectivelyblocks or enables the respective color feed line, b) the respectivecolor control device is controlled by a control signal that includescontrol air supplied by additional docking points onto which the colorextractor can dock, and c) the control signal is passed from the colorextractor via an associated additional docking point to the respectivecolor control device, so that the control signal reaches the respectivecolor control device only when the color extractor is docked onto theassociated additional docking point.
 4. The painting robot according toclaim 1, wherein the color extractor can be moved relative to thedocking points of the color bar.
 5. The painting robot according toclaim 1, wherein a control loop is provided for positioning the colorextractor in relation to the docking points of the color bar, whichcontrol loop contains a measuring device measuring the position of thecolor extractor in relation to the docking points and compares themeasured values with stored nominal position values in order to bringthe measured positions into correspondence with the nominal values, andwherein at least one centering element is arranged at least on one ofthe color extractor or the docking points, said at least one centeringelement engaging in a receiving opening of the other of the colorextractor or the docking points during a docking process.
 6. Thepainting robot according to claim 1, wherein a drive, which can becontrolled by stored control data, is provided for relative movementbetween the color extractor and the docking points of the color changer.7. The painting robot according to claim 1, further comprising: a) afirst flushing circuit for flushing the docking points of the colorchanger with a flushing agent, and b) a second flushing circuit forflushing the common color line between the color changer and theatomizer with a flushing agent, wherein the first flushing circuit isseparate from the second flushing circuit so that the docking points canbe flushed independently of and separately from the common color line.8. The painting robot according to claim 7, wherein a) a separatingvalve is arranged in the common color line in the color extractor inorder to separate the first and second flushing circuits from oneanother, b) the first flushing circuit leads from a first flushing agentfeed line via a first flushing agent valve into the common color lineupstream of the separating valve to the docking points through a firstreturn valve into a first return line, c) the second flushing circuitleads from a second flushing agent feed line via a second flushing agentvalve through the common color line downstream of the separating valveto the atomizer via a second return valve into a second return line or amain needle valve of the atomizer.
 9. The painting robot according toclaim 1, wherein a flushing agent feed line opens into the common colorline upstream of a main needle valve of the atomizer via a firstflushing agent valve arranged in the atomizer to push the paintremaining in the common color line back through the color changer intothe associated color feed line for later reuse.
 10. The painting robotaccording to claim 9, further comprising: a) a flushing agent meteringmeans which is arranged in the flushing agent feed line upstream of thefirst flushing agent valve and which can push the flushing agent locatedin the flushing agent metering means into the common color line when thefirst flushing agent valve is opened, and b) a second flushing agentvalve for controllably filling the flushing agent metering means via theflushing agent feed line.
 11. The painting robot according to claim 10,wherein a) the flushing agent metering means has a metering volume whichis substantially identical to a filling volume of the common color linebetween a respective docking point and the main needle valve of theatomizer.
 12. The painting robot according to claim 1, furthercomprising a clamping device for mechanically clamping the colorextractor and a respective docking point in the docked state.
 13. Thepainting robot according to claim 12, wherein the clamping devicecomprises a groove with an undercut, onto which a movable clampingelement latches.
 14. The painting robot according to claim 13, whereinthe groove has the undercut only on an upper groove flank, and does nothave the undercut on a lower groove flank.
 15. The painting robotaccording to claim 1, further comprising a) a paint pressure regulatorwhich is mounted in or on the distal robot arm, and b) a metering pumpwhich is mounted in or on the distal robot arm for metering the paint tobe applied, wherein the metering pump is connected on the outlet side tothe color changer and on an inlet side to the atomizer, and c) anactuator for moving the color extractor relative to the docking points,wherein the actuator is arranged in the distal robot arm.
 16. Thepainting robot according to claim 1, further comprising a commonconnection block, in which a paint pressure regulator, an actuator, anda metering pump are arranged.
 17. The painting robot according to claim1, wherein the color feed lines are connected to the color changer by acolor connection, wherein the color connection includes: a) a receivingbore in the color changer for the insertion of the associated color feedline, b) an angled clamping surface at an end of the associated colorfeed line, c) a clamping bore which runs in the color changersubstantially at a right angle to the receiving bore and opens into thereceiving bore, wherein the clamping bore has an inner thread, d) a freeend of a clamping screw which is screwed into the clamping bore and, ina screwed-in state, presses against the clamping surface of theassociated color feed line and axially secures and clamps the associatedcolor feed line.
 18. The painting robot according to claim 1, whereintwo color lines alternately convey different colors to the atomizer andcan be flushed alternately, and wherein a movable part of the colorchanger has first devices for flushing at least one docking inlet andsecond devices for flushing the two color lines as far as a valvearrangement located in the atomizer and is connected to the first andsecond devices.
 19. The painting robot according to claim 18, furthercomprising an automatically controllable first valve, which is designedas a needle valve and the needle valve is displaceable in the interiorof a first valve housing part, and an automatically controllable secondvalve which is connected to said first valve; wherein a controlled inletor outlet of the second valve is arranged in the interior of the firstvalve housing part or is connected to the interior of the first valvehousing part via a line.
 20. The painting robot according to claim 1,further comprising: a paint pressure regulator and a metering pump,wherein the paint pressure regulator and the metering pump areintegrated without any connecting tube in a common connection block,wherein the paint pressure regulator is installed directly on themetering pump.
 21. The painting robot according to claim 1, furthercomprising: a docking carriage in the color changer which isdisplaceable relative to the color bar, wherein the color bar is formedby a plurality of modules releasably attached to one another, each ofthe modules contains at least one color valve and at least one dockingpoint connected to the at least one color valve.
 22. The painting robotaccording to claim 21, wherein each of the modules contains at least twocolor valves which are inserted with respective central axestransversely or perpendicularly in a side face of the color bar which isparallel to the longitudinal direction of the color bar, wherein thecentral axes of the color valves of the module are offset relative toone another in the longitudinal direction of the color bar by a certainvalue and are spaced apart in the direction vertical to the longitudinaldirection by a certain value, and these values are identical within atleast one of the modules, and wherein the docking points are located onthe side of the color bar opposite to said side face and are offsetrelative to one another and spaced apart from one another by the samevalues as the central axes of the color valves.
 23. The painting robotaccording to claim 22, wherein each of the modules has transverse faceswith a curved profile which extend transversely to the side face from anupper side of the color bar to an underside of the color bar, thetransverse faces adjacent the modules adjoin one another, and whereinthe transverse faces, proceeding from the upper side and from theunderside, run transversely or perpendicularly relative to the upperside and the underside, bend in a direction parallel to the longitudinaldirection of the color bar, and run again transversely orperpendicularly to the upper side and the underside, wherein thetransverse faces of each of the modules run parallel to one another oras a mirror image relative to one another.
 24. The painting robotaccording to claim 21, wherein at least one connection element, whichcan be connected to an external color line and has a central axis, isinserted with the central axis perpendicularly to an end face inclinedat an angle to the longitudinal direction of the color bar on an upperside of each of the modules and is connected to a corresponding colorvalve in the interior of each of the modules.
 25. The painting robotaccording to claim 21, wherein each of the modules has for the at leastone color valve contained in the respective module two connectionelements which can be connected to external lines and which areconnected inside the modules to the interior of the at least one colorvalve for the purpose of color circulation.
 26. The painting robotaccording to claim 25, wherein the at least one color valves is designedas a needle valves with a tubular housing part containing the valve seatand an additional housing part containing a drive part for the needlevalve, and wherein at least one of bores, hollow lines, and pipes in aone-piece module body lead from the connection elements to the tubularhousing part of a corresponding color valve for the purpose of paintcirculation as far as the valve seat.
 27. The painting robot accordingto claim 26, wherein a further bore or pipe running in a substantiallyrectilinear manner for compressed air or another control medium foractuating the color valve leads in the module body from a respectivedocking point of the module to the housing part containing the drivepart in each of the at least one color valve of the modules or into thetubular housing part.
 28. The painting robot according to claim 21,wherein at least one module is insertable into the color bar, the atleast one docking point of the at least one module is among a row ofdocking points of the respective modules adjacent to each other andparallel to the longitudinal direction of the color bar and is connectedin the interior of the at least one module via a corresponding colorvalve to a connection body of the at least one module, to which there isconnected a pigging tube for a pig which conveys the color material tothe at least one module.
 29. The painting robot according to claim 28,wherein, next to the connection body of the pigging tube, there is atleast one additional connection body for a return line and for a linefor supplying a pushing medium for pushing the pig back through thepigging tube, and wherein the at least one module contains a respectivevalve for the return line and for the line for supplying the pushingmedium.
 30. The painting robot of claim 1, wherein the color extractorand the docking points can be displaced relative to one another.